What Causes Visible Smile Lines, and What Softens Their Appearance

Key Takeaways

• Smile lines are a feature of facial anatomy. They run from the sides of the nose to the corners of the mouth, and they exist on almost every face, because that is where the muscles lifting the upper lip attach to skin.
• There is rarely one cause. Collagen and elastin decline, midface volume shifts, repeated expression, sun exposure and genetics all contribute, in different proportions on different faces.
• Sun protection is the most substantiated thing you can do. In a randomized trial, daily broad-spectrum sunscreen produced measurably less accumulated skin aging than occasional use.
• Topicals work on skin quality. Peptides, Retinoids, Exfoliating Acids and sustained hydration help skin look smoother. None of them changes the anatomy underneath.

What Are Smile Lines (Nasolabial Folds)?

Smile lines, laugh lines, and nasolabial folds all describe the same thing: the two creases that run from either side of the nose down toward the corners of the mouth. Nasolabial fold is the clinical term, and it's the one you're likely to see in a dermatologist's notes or a medical journal. If you've noticed them for the first time, they're not a sign that anything has gone wrong. They are a feature of facial anatomy, and they show up on faces of every age.

Smile lines can become noticeable in your twenties, long before most other visible changes, because movement produces them. Every smile draws the same skin along the same path. What changes with age is how deeply the fold sets, and how readily the skin springs back. So the useful question is what makes them look deeper, and which of those things you can influence.

What Causes Visible Smile Lines?

Five factors do most of the work. On any given face they combine in a different mix, which is why two people of the same age can have very different folds.

Collagen and Elastin Decline

Collagen gives skin its structure and elastin lets it recoil. Both decrease steadily from early adulthood. As they visibly thin, skin recovers more slowly from the same repeated fold, and a crease that used to disappear the moment you stopped smiling begins to linger.

The Face Loses Volume and Shifts Structure

This is the cause most often missed, and the reason some folds resist skincare entirely. A 2024 anatomical review in Diagnostics described nasolabial folds as having several distinct structural origins. In some faces, the fold reflects a lack of superficial fat next to the nose. In others, the fat compartment above the crease can visibly enlarge while the fat below it can look diminished, so tissue appears to fold over a fixed line. The ligaments holding those compartments in place also lose resilience over time.

Part of what you see is skin, and part of it is the shape underneath. The two respond to very different things.

Repeated Expression

The same review noted that specific fibers of the muscles that elevate the upper lip attach directly to the skin near the fold. When those muscles contract, they pull on that exact line. This is a mechanical explanation for something people notice intuitively, which is that the fold sits precisely where the face moves most.

Sun Exposure

Ultraviolet exposure accelerates the breakdown of collagen and elastin, so photoaging shows up as loss of visible firmness, pigment, and the look of deepening lines. It is also the single largest contributor you have direct control over.

Sleep Position, Smoking, Weight Change and Genetics

Consistent side sleeping presses one side of the face into a pillow for hours at a time. Smoking both restricts blood flow to the skin and repeats a pursing motion around the mouth. Significant weight loss can visibly reduce facial volume and make the look of an existing fold more prominent. And bone structure and skin thickness are inherited, so smile lines run in families and some people simply never develop deep ones.

Why Some Smile Lines Look Deeper Than Others

Visible smile lines usually mean more than one of the factors above is acting at once. Where a fold reflects mainly surface change, it tends to visibly soften with consistent care. Where it reflects bone structure, a flatter midface or fat that has shifted position, it holds its depth regardless of what goes on top of it. That is the practical reason two people with the same skincare routine, the same age and the same sun history can see very different results from it.

Smile Lines, Marionette Lines and Other Wrinkles Around the Mouth

Several different lines around the mouth get treated as one problem, and they're not the same. Smile lines, or laugh lines, run from the sides of the nose to the corners of the mouth. Marionette lines run downward from the corners of the mouth toward the jaw. Vertical lip lines sit on and just above the lip itself. They share causes, so the same daily care helps all three, but they sit in different places, and they set at different rates. Identify which one you are looking at before you change anything in your routine.

What Actually Softens the Appearance of Visible Smile Lines?

The evidence is strongest for five ingredient categories. Every one works on the skin rather than the structure underneath it: how smooth it looks, how well it holds water, how quickly it shows visible change. That's why no cream closes the fold itself, whatever the packaging says. We would reach for them in this order.

Daily Broad-Spectrum SPF

This is first because it is the best substantiated, and the newest evidence is also the closest to the face. In a 2023 randomized trial in the Journal of the European Academy of Dermatology and Venereology, 290 women aged 30 to 65, across skin types II to VI, applied an SPF 60 sunscreen twice daily for a year while a control group carried on with their usual routine. Fifteen dermatologists graded standardized photographs at the start and at day 365. In the sunscreen group, several visible facial aging signs progressed 30 to 50% less, among them the look of marionette lines and the wrinkles that come from sagging.

The longer view agrees. In a randomized trial published in the Annals of Internal Medicine in 2013, 903 adults under 55 were assigned either daily broad-spectrum sunscreen or discretionary use, and over four-and-a-half-years, skin aging was 24% lower in the daily group. That group showed no visible increase in skin aging at all.

Both trials measured sunscreen slowing the accumulation of visible change, not undoing change already present. That makes daily SPF preventive.

Our Multimodal Defender Balm Broad Spectrum SPF 30 uses 20.4% zinc oxide as its active, a mineral filter offering broad-spectrum protection against UVA and UVB rays, and it is formulated to visibly improve the look of dark spots and fine lines at the same time.

Peptides

Peptides are short chains of amino acids that signal to skin cells. Several have clinical support for improving the appearance of roughness and wrinkle depth in photoaged skin, and as a category they are better tolerated than Retinoids, which matters in an area that moves frequently and can be easily over-treated. Copper Tripeptide-1 has a further role in the pathways involved in collagen formation.

The SMOOTH Dynamic Wrinkle Defense Serum is formulated around a Multi-Peptide Complex including Copper Tripeptide-1, Palmitoyl Tripeptide-5 and Acetyl Hexapeptide-8, alongside Centella Asiatica and Vegan Silk Protein, to help visibly soften the look of existing lines and support skin's resilience.

Retinoids

Retinoids are the most studied topical category for photoaged skin, with evidence for visibly smoother texture and less noticeable lines over months of consistent use. But the category is broad, and the differences within it matter.

Prescription Tretinoin has the strongest evidence. Over-the-counter Retinol is a step gentler, and Retinyl Esters such as Retinyl Linoleate and Retinyl Palmitate, which are what U Beauty formulas use, sit at the gentlest end. They convert more slowly in the skin, which means a milder effect and less visible irritation. If you are deciding between them, our guide to Retinol versus Retinoids sets out the distinction properly.

Gentle Exfoliating Acids

Alpha Hydroxy Acids help visibly refine the skin's surface, which changes how light meets it and how a crease reads. The Resurfacing Compound combines Glycolic, Lactobionic, and Mandelic Acids with Sodium Ascorbyl Phosphate, a Stable Vitamin C derivative, so the surface work and the antioxidant work can happen in a single step. The point of a multifunctional formula here is restraint: fewer products layered over an area that is already moving frequently.

A Moisturizer That Holds Hydration

Well-hydrated skin looks plumper, and a visibly plumper surface makes a fold appear more shallow. A moisturizer earns its place here by holding that hydration for longer than an hour. The SUPER Hydrator uses five types of Hyaluronic Acid with Squalane and a Peptide Complex to hydrate for up to 48 hours, so the effect holds through the day.

What Skincare Can and Can't Do Here

Topical skincare acts on the skin: its hydration, its surface, its collagen and elastin, its capacity to recover from being folded. Used consistently, that is enough to help make smile lines look softer and to slow how quickly they deepen.

What skincare does not do is change facial structure. If a fold is driven mainly by where fat compartments sit, by ligament laxity or by the underlying bone, no cream reaches that layer, and any claim that one does is worth treating with suspicion. No cosmetic product removes a fold completely.

We build formulas the way we do because the skin around the mouth is in near-constant motion and can be easily over-treated. Fewer, better-targeted products applied consistently serve this area better than an eight-step routine of competing actives.

Frequently Asked Questions

At what age do smile lines appear?

Earlier than most people expect. They can become noticeable in the twenties, since repeated movement is a driver from the start. They typically become more pronounced through the thirties and forties as collagen and elastin decline and midface volume shifts.

Can you get rid of smile lines completely?

Not with skincare. Consistent topical care can help visibly soften how they look and slow how quickly they deepen. Removing them entirely would mean changing the underlying facial structure, which no cream reaches.

Can you visibly soften the look of smile lines naturally?

Up to a point. Daily sun protection, staying hydrated, not smoking, and sleeping off your side all act on real causes and cost nothing. Home remedies that claim to remove a fold do not hold up: coconut oil, egg white and lemon juice do nothing structurally, and the acidic ones can irritate thin skin around the mouth.

Do facial exercises help visible smile lines?

The evidence is limited and mixed. Facial exercise has been studied mainly for cheek fullness rather than for nasolabial folds specifically, and results have been modest. Given that repeated muscle movement is one of the causes, exercises that emphasize that movement are unlikely to be the most useful place to put your effort.

Does drinking water reduce smile lines?

Hydration status affects how plump skin looks, so it matters. But drinking more water will not visibly soften an established fold on its own. Topical hydration that holds moisture in the skin over time does more for how the area looks than water intake alone.